Coping with Spam Using Eudora 6.0

Handout GAG 341 -- June 2006

What is Spam?

Spam is a slang term for unsolicited commercial email.

Why Do I Get Spam?

It's simple; because your email address is widely distributed, it gets put into electronic mailing lists. If you have put your email address on a webpage, used it to post to an online forum or newsgroup, or included it when filling out a form on a commercial website, more than likely your address will wind up in a commercial mailing list.

Some Windows viruses (particularly the Lovgate series) are believed to harvest email addresses from the files of the machines they infect and send them to spammers. Keep in mind, the addresses of staff members at Iowa State University are public records by Iowa law and must be made available to whoever asks. And yes, unless you specifically tell it not to, your student email address can be sold by the university to selected mailers.

How Can I Make Spam Go Away?

You will probably never be able to completely eliminate spam from your inbox. Even the best of filters will only catch part of the junk mail sent to you. Even if you change your email address, it will only give you a brief respite until your new address is harvested from somewhere on the Web. However, there are steps you can take to reduce the amount of spam you receive.

• Unsubscribe from groups you are no longer using

  Some of the spam you receive probably is not precisely spam. If you signed up for something on a webpage, such as requesting information or downloading or registering a software package you purchased, you may have inadvertently asked them to send you mail - and that is not spam. If you really have subscribed to a newsletter and you no longer want to receive it, unsubscribe from it. Check the text of the message; there is often an unsubscribe link or an email address to send a message to be removed from the list. However, do not try this on unsolicited email messages, since less scrupulous spammers will simply use your unsubscribe request as an indication that your email address is active and send you more spam.

• Use an alternative email address in commercial webpages

  Instead of using your primary email address to sign in to commercial webpages, establish another account with one of the free providers like Yahoo, Netscape, or Hotmail, and use that address instead. (Yahoo is especially good, as it allows you to create hundreds of unique addresses.) That way, you will keep your spam separate from the real messages. Be polite, though; log in to those accounts periodically and delete the spam.

• Use filters in your email client

  Most of the email clients you can use to read email give you filters to sort your mail into different mailboxes based on sender, subject, and other criteria. Those filters can be used to make spam go away as well.

  To help your mail client in this quest, Iowa State has provided a "spam tagging" system called PerlMX. PerlMX examines all the messages that come to @iastate.edu addresses from outside the university and calculates the probability that the message is spam. That information is placed in a special header that you will not normally see, but which most mail clients use to filter the email into spam and non-spam categories.

Using Filters in Eudora 6.0

Eudora Pro 6.0 has a spam filtering option built in. It uses Bayesian filtering and is a "trainable" filter, that is, you tell it which messages are legitimate and which are spam, and it gradually learns your mail mix. After a while, it becomes very accurate. Junk mail messages, or spam, are moved into the Junk folder, and are automatically deleted after 30 days. You can open the Junk folder, read messages that have been misfiled, and move them back into the In mailbox. In addition to the built-in spam filters, you can also use custom filters of your own creation.

Built-in Junk Mail Feature

Training Junk Filters in Eudora

When it is installed, Eudora has a generic idea of what spam is. It will move messages it believes to be spam into the Junk folder. To increase the accuracy of the filters, you must train Eudora in what you believe is or is not spam.

To identify a message as spam, highlight the message in the In mailbox message list and select "Junk" from the Message menu. You may also press <Ctrl>/J in Windows or <Command>/J on a Macintosh to junk the highlighted message. You can also hold down <Ctrl> in Windows or <Command> on a Mac and click multiple messages to junk several in one operation. Junking a message not only moves the offending message to the Junk folder, but it gives Eudora another example of what your spam looks like.

Periodically, you should check the Junk folder to see if any legitimate messages have been misfiled. If there are, highlight them and select "Not Junk" from the Message menu. The messages will be returned to the In mailbox. Eudora will learn that messages like these are not spam, and in addition, the sender of the message will be added to your Eudora address book.

Activating the Whitelist

A whitelist is a list of addresses you accept mail from, no matter what it looks like. Eudora 6.0 can do this by accepting mail from any address found in the Eudora address book. This feature is turned off by default, but you can turn it on like this:

1. Select "Tools" and then "Options" for Windows or "Special" and then "Settings" for a Macintosh.
2. Choose "Junk Mail" in the menu at the left.
3. Check "Mail isn't junk if sender is in an address book".
4. Click "OK".

One disadvantage of this feature is that the addresses from all the messages you unjunk wind up in your regular address book along with the addresses and nicknames you really want to use. In the Windows version of Eudora 6.0 you can fix this by putting those addresses in a special address book:

1. Select "Tools" and then "Options".
2. Choose "Junk Mail Extras" in the menu at the left.
3. Under Addr book for 'Not Junk'ed Senders, enter a name like NotJunkMail.
4. Click "OK".

Adjusting the Junk Threshold¹

Just like PerlMX, Eudora creates a score for each message which is the probability the message is spam. When Eudora is installed, it assumes that messages with a score of 50 or higher should be junked. If you are getting too much spam in your In mailbox and training does not seem to help, try lowering the threshold to 40 or even 30, like this:

1. Select "Tools" and then "Options" for Windows or "Special" and then "Settings" for a Macintosh.
2. Choose "Junk Mail" from the menu on the left.
3. Under Consider mail junk if score is at least, move the slider to a lower value.
4. Click "OK".

In the same way, if you are getting too many false positives try increasing the value from 50 to 60 or higher.

Additional Filters

To create additional filters to automatically file messages into a folder or just automatically delete them, do the following:

1. If the message is in the Junk folder, highlight it and select "Message" and then "Not Junk".
2. In the In mailbox, highlight the message and select "Special" and then "Make Filter".
3. The filter can be based on the From, Any Recipient or Subject lines. Select one.
4. If you select Subject, make sure the subject line does not contain any specific information, like a date. Eudora simply checks to see if the string given appears in the Subject line; it is not an exact match, so edit out anything that will not appear again.
5. Under Action choose "Transfer to new mailbox", "Transfer to existing" or "Delete Message".
6. If you select "Transfer to new mailbox", enter a name for the mailbox. If you select "Transfer to existing", click the "In" button and select a mailbox.
7. Click "Create Filter".

Using PerlMX Headers Explicitly

Eudora 6.0 already uses the PerlMX headers, the "spam tagging" system Iowa State uses to help your mail client identify spam more easily. It recognizes the headers added by several popular spam tagging systems and uses them in its calculations. However, you can use PerlMX scores directly like this:

• In Windows, select "Tools" and then "Filters". On a Macintosh, select "Window" and then "Filters".
• Click "New" in the lower left-hand corner of the Filters dialog box.
• Under Header, enter X-Perlmx-Spam.
• In the Contains field, enter Gauge=XXXXX. This will filter on a PerlMX score of 50 percent (one X for each ten percent; add or subtract Xs as needed).
• Under Actions, choose "Junk" from the pull-down menu for the first action.
• Choose "Skip Rest" from the pull-down menu for the second action.
• Close the Filters window and save the changes.

If you want to set the PerlMX filter to a value other than every ten percent, you will need to create filters for the next ten percent up and for each of the gauges below that percentage. If you would like to set the threshold to 47 percent, you will need separate filters for the X-Perlmx-Spam header containing Gauge=XXXXX (50 percent), Gauge=XXXXIIIIIIIII (49 percent), Gauge=XXXXIIIIIIII (48 percent), and Gauge=XXXXIIIIIII (47 percent). Since the PerlMX headers are not an exact science anyway, this may be more effort than it is worth.

Copyright © 1995-2008, Iowa State University of Science and Technology. All rights reserved.

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